Rotary radial piston pump



Feb. 13, 1940. J. B. HAwLEY. JR 2,190,065

l ROTARY RAISIAL PISTON PUMP Fi1ed Aug. `28. 1936 s sheets-sheet 1 Feb. 13, 1940. J. B. HAwLEY. JR 2,190,065

ROTARY RADIALPISTON PUMP Filed Aug. 28, 1936 3 Sheets-Sheet `2 'ffy-.7' Waff/5% Feb. 13, 1940. J. B. HAWLEY, JR

ROTARY RADIAL PISTON PUMP 3 Sheets-Sheet 3 fai f7 -LILLL Ifrll Patented Feb. 13, 1940 UNITED sTaTEs ROTARY RADIAL PISTON PURIP John B. Hawley, Jr., Minneapolis, Minn., assignor, to Reconstruction Finance Corporation', Minneapolis, Minn., a corporation oi' the United States Applicata August as, 193s, serial No. 98,300

6 Claims.

This invention relates to a liquid` pump of the rotary piston type. Such'pumps are now largely used for furnishing liquid, such as oil under pressure, for the operation of hydraulic presses, motors and other machines operated by a liquid such as oil under pressure.

It is an object of this invention to provide such a rotary pump of high durability and efflciency. This requires very accurate construction and arrangement of 'the parts so that a minimum of wear is had.

It is another object of the invention to provide a rotary radial piston pump in which the pistons dial line so that there'is no tendency to move the pistons laterally against the cylinder wall.

It is a further object of the invention to provide a rotary pump of the piston type in which the pistons reciprocate in cylinders formed in a rotating cylinder block, said pistons being carried on cross heads guided in said block and having rollers thereon engaging with the inner side of a rotating ring provided with. a full floating mounting. i

25 It is still another object of the invention to provide a rotary pump of the piston type comprising a pintle flexibly supported at one end and having roller bearings spaced'longitudinally thereof to maintain said pintle concentric with 30 said block, said cylinder block also rotating on roller bearings carried in the housing of said pump.

It is still another object of the invention to provide such a pump as set forth in the preceding paragraph in which the said pintle is provided with spaced passages extending longitudinally thereof, through'which the liquid enters and is discharged respectively, said passages having ports communicating with ports leading into @o the cylinders formed in said cylinder block, saidv blocky having cylinders `spaced longitudinally thereof and having a common port/communicating with said ports in said pintle.

It is another object of the invention to provide a rotary pump of the radial piston type having a stationary pintle and a cylinder block rotatable thereabout, said block ruiming on spaced bearings carried on said pintle and being spaced -vvery slightly vfrom said pintle between said bearings together with means for forcing oil through said lpintle and about said pintle between said bearings tolubricate said pintleand bearings.

It is another object vof the invention to provide a rotary pump of the radial piston type 55 comprising a housing, a pintle supported at one are reciprocated by forces acting in a direct ra- (Cl. ID3- 161) end and extending into said housing, a cylinder block rotatable about saidpintle on bearings disposed about said pintle and also on bearings sup- `ported in saidhousing, said cylinder block having radial cylinders formed therein, pistons re'- 6 ciprocable in said cylinders having roller-carrying means secured thereto, a ring rotatable about said cylinder block on bearings carried in said housing and means for positively lubricating all of said bearings. v

Itis another objectof the invention to provide a rotary pump of the radial piston type com? prising .a pintle iiexibly secured at one end, a housing into which said pintle extends, a cylinder block rotatable about said pintle on roller bearings carried by said pintle and spaced longitudinally thereof and on bearings carried by said housing of greater diameter than said rst mentioned bearings and adjacent the fixed end of said pintle together with means for permit` 20 ting flexing of said pintle laterally in said last mentioned bearings to permit said bearings to maintain a concentric position.

These and other objects and advantages of the invention will be fully set forth in the follow# ing description madein connection with the accompanying drawings, in which like reference characters refer to similar parts throughout the severalA views and in which;

Fig. 1 is a view partly in side elevation and 80 partly in vertical section taken substantially online l--l of Fig. 3;

Fig. 2 is a view partly in side elevation and partly in vertical section taken substantially on line 2--2 of Fig; 3;' 315A Fig. 3 is a vertical section taken substantially on line 3-3 of Fig. l, all of said sections Abeing taken as indicated by the arrows;

Fig. 4 is a View in side elevation of the pintle used, a part being broken away and another part -shown in vertical section;

Fig. 5 is a vertical section taken on line 5-5 of Fig. 4 as indicated by the arrows;

Fig. 6 is a view partly in side elevation `and partly in vertical section of a piston assembly; Fig. 'l'` is a bottom plan view of the parts shown in Fig. 6 or as seen from line 'l--l looking in the direction of the arrows;

Fig. 8 is a view similar to Fig. 2 showing a modification; 50

Fig. 9 is a View similar to Fig. 7 showing a diierent construction;

Fig. 10 is a'view partly in side elevation and partly in vertical section of the parts shown in Fig. 9; and 55 Fig. l1 is a view in side elevation of the piston assembly shown in Figs. 9 and 10.

Referring to the drawings, a pump of the rotary radial piston type is shown comprising a housing or casing |Il. This housing has a suitable base portion Illa provided at corners with apertures |017 adapted to receive foundation bolts. Said housing I0 is roughly rectangular in shape with rounded corners at its upper side and is provided with suitable strengthening ribs |0c. A front cover or bearing plate I I is secured to one sideof housing lll by the headed cap screws I2. Cover is provided with holes Ila to give access to the housing and said holes are covered by plates ||b bolted to plate Il. A rear cover or bearing plate I3 is also provided and secured to the side of the housing by bolts I3a. A suction or inlet member or nozzle I4 is provided, the same having a flange |4a bolted to the rear cover I3 by the screws I 5, said screws passing through the holes |4b in ange I 4a. Member I4 has an inlet opening or bore |4c and a pipe 6 extends from member |4 and bore I 4c to an adapter member I1, pipe |6 being very rigidly secured to both members I4 and I1. A discharge member or nozzle I8 has a flange |8a secured to rear cover I3 at the side opposite that to which memberl I5 is secured, member I8 being secured by screws I9 passing through the holes |8b. Member I8 has a discharge outlet or bore |8c and a discharge pipe is rigidly secured to mem` ber I8 and communicates with bore |80, said pipe extending to and being rigidly secured at its other end to an adapter member 2|. Members |1 and 2| are similar in construction but reversely arranged and the same have passages |1a and 2|a formed therein with which pipes I6 and 2I| communicate and which they aline respectively. A pintle member 22 is disposed between members |1 and 2| and is rigidly clamped therebetween by the headed and nutted bolts 23 passing at each side of said pintle. Pintle member 22 has annular slots or grooves 22a arranged in the sides thereof and members I1 and 2| have ribs |1b and 2lb formed thereon tting in said Slots 22a. GasketI members |1c are disposed in the bottom of slots 22a and are engaged by the tops of the 'annular ribsA |1b and 2lb. Pintle member 22 extends through the rear cover I3 and into the housing I0. A cover plate 24 hasan opening through which pintle 22 passes, said cover being secured to the rear cover I3 by bolts 25. As shown in Fig. 2 the portion of pintle 22 disposed between members |1 and 2| is substantially rectangular in cross section. The portion of the pintle projecting beyond members I1 and 2| is cylindrical. Plate 24 has a recess 24a at itsv outer side adjacent pintle 22 and the portion adjacent said pintle as shown in Fig. A3 is rectangular in radial cross section. A leather washer or ring 21 of angle shape in cross section extends around said recess with its angle directed inwardly and a ring 28 of cork or similar material ts in said washer and recess. A plate 30 is secured to the outer side of plate 24 by the end 22h of pintle member 22. A cap plate 35 is secured to the inner end of pintle 22 by the' circumferentially spaced screws a and is centrally bored and threaded to receive a plug 36. Pintle 22 is provided with a comparatively small axial bore 22e which is enlarged at its outer end to receive a lubricating connection 31. Oil passages 22cc extend from bore 22e to the cylindrical surface of pintle 22 between bearings 33 and 34. Between bearings 33and 34 the cylinder block is very accurately bored to have a very small clearance about pintle 22. In practice this clearance varies from one to five thousandths according to the diameter of the pintle. ring 39 extends about pintle 22 adjacent bearing 33, said pintle at this point being of slightly smaller diameter than its diameter within the inner shell of bearing 33. Pintle 22 has a plurality of inlet and outlet passages 22d extending longitudinally thereof. The inlet passages communicate with opening |1a while the outlet passages communicate with opening 2Ia. At the inner portion of the pintle substantially centrally between the bearings 33 and 34 the pintle has openings or ports 22e extending to its periphery from the passages 22d. Pintle 22 between the ring 39 and its reduced portion 22h is provided with a shell 22j of some bearing metal or antifriction metal, such as bronze, said shell being rmly secured to said pintle. Said pintle at each side of the ports 22e and at equal distances therefrom is provided with narrow grooves 22g of lsubstantially the same circumferential extent as the openings or ports 22e. Said grooves are connected by drilled holes to the inlet and outlet ports respectively on the opposite side of the pintle. These are provided to equalize the pressure radially or transversely of pintle 22.

'I'he cylinder vblock 32 is provided with a plurality of radial bores 32a, `forming cylinders, and these bores have openings or ports 32b at their lower ends at the inner side of the block adjacent the pintle 22 which aline with the ports 22e as shownin Fig. 3. Block 32 at the outer side of each bore or cylinder 32a has a slot with parallel sides and of substantially the same width as the diameter of the cylinder bore. Cross heads 40 are movable radially in said slots and carry roller bearings 4| in which is journaled the cross head roller or pin 42. The cross heads 40 have secured thereto the pistons 43. Each piston comprises a shell 43a ofy brass or similar metal through which extends the cylindrical portion 40a of the cross head 40, the lower reduced and threaded end 40h of which receives the securing nut 44. Nut 44 is provided with a plurality of chamfered slots 44a for the application of a tightening tool. Portion 40a is provided with a plurality of annular grooves 40e adapted to re` ceive oil. It will be noted that the lower end ot shell 43a-is quite thin and that there is a space between its inner side and the nut 44. Pin 42 has an integral enlargement'or collar 42a there- A snap v fin on at its central portion between the cross' heads 4Il'and said pin has secured at each outer end adjacent cross heads 40 the rollers 45. The cylinder block 32 also rotates on roller bearings 46 mounted respectively in the front and rear cover plates I and I3. A bearing lock plate 41 is secured to the front end of member 32 by the bolts 48, the s ame engaging the outer side of front bearings 46. A locking plate 49 is also secured to the rear end of member 32 by bolts 50 and engages` the outer side of rear bearing 46. Plate 48 also engagesv the end of a. spacer bushing 5|.

53 passing through flange 52b into member 32.-

Passages 52e extend through portion 52a and flange 52h for lubrication purposes. The drive shaft .52 extends .outwardly through an end cover member 54 having a flange secured to the front housing cover i l by the circumferentially spaced screws 55. Cover plate 54 also has an inner flange 54a engaging the outer side of front bearing 48. Plate 54 also has a recess in its outer side which forms about shaft 52 a recess rectangular in radial cross section. A washer or ring 54e of leather or similar material is disposed in said recess,

the same being of angle shape in cross section and 'having its angle directed inwardly. A ring 54d of cork or similar material is disposed within the angle of washer 54e and fills the remainder of said recess. Members 54e and 54d thus form with plate 54 a yielding seal about shaft 52. An end cover plate 54e is secured to an annular outwardly projecting flange on plate 54, the inner edge of which is spaced slightly from shaft 52.

The rollers 45 and the collar 42a engage at their outer sides a ring 56 which rotates and has a floating mounting on roller bearings.. Ring 58 has secured to each side thereof by screws 59 the annular side plates 51 and58 having cylindrical portions through which the cylindrical end portions of the cylindef.` block extend. Plates 5l and 58 are carried on the roller bearings lillalso carried in a ring or rotor guide member 8|. Plates 5l and 58 have oil passages 51a and 58a formed respectively therethrough. The rotor guide member 6l has ak slot 6 la extending trans- 4 versely thereof at its bottom and shafts or pins 82 extend across this slot having mounted thereon rollers 83 carried on roller bearings 84 surrounding the shaftsw'. The rollers 83 roll upon' the flat surface of a hardened plate 65 secured by screws 8,8 to a larger plate 81 mounted on the housing i9. Said roller guide 8l has a similar slot Gib atits top across which extend the shafts 68 having mounted thereon rollers 89 similar to rollers 83 and also mounted on roller bearings surrounding the shafts 68. The rollers 89 engage the flat under surface of a hardened plate i8 also secured in any suitable manner to the top of housing ia. The member 6l also has slots 8de adjacent its top and'bottom and at either side thereof, across which extend the pins or shafts 1l on which are mounted rollers 12, said rollers being mounted on roller bearings 13 surrounding the pins or shafts 1l. The rollers l2 engage against the flat vertical surface of a plate 18, there being such a plate at each side of member 8l, said plates being suitably secured to the housing I8. Member 6l has secured thereto a plate l5 having projecting lugs 15a in which is secured a pin or shaft i8, held in place by the pins or keys 11 extending therethrough at the `outer sides of lugs a. Pin 18 extends through amember t8 which is thus connected to member 15 and member i8 has projecting spaced lugs 18a through which extends a pin or shaft 19 held in place by pins or keys 88 extending therethrough adjacent its ends and at the outer sides of lugs llia. Members l5, 18 and attached parts are provided to form a connection to the means which moves the rotor guide 6I. This movement inthe pumps is sometimes done manually and at other times is done byy automatic control means. Iii/Fig. 8 a modied form of connection for l the nozzles and pintle is shown. The intake member or nozzle 85 corresponding to member I4 is shown, the same having the `intake opening 85a,

the .attaching flange 85h with holes 85c there.

through as well as the flange 85d adapted to engage the housing and to which it will be connected by bolts passing through the holes 85e. Member 85 is connected to an adapter member 85 by a pipe 89 which is of U-shape. Pipe 89 thus has two right angle bends therein and itsends Awill be securely and rigidly fastened to members 85 and 86. Pipe 89 will, of course, communicate with the bore 85a and at its other end communicates with the bore 86a of member 86. A discharge member 81 similar to member 85 is provided, the same also having a bore 81a, the flange 81h with holes 81e therethrough and the attaching flange 81d provided with the holes 81e .adapted to re-l ceive attaching bolts. Member 81 is connected to an adapter member 88 similar to member 88 by pipe 89a, which pipe is also of U-shape and similar to pipe 89. Pipe 89a will be firmly connectedat its ends to members 81 and 88 and communicates with bore 81a and the bore or passage 88a in member 88. A pintle member 98 is provided having a portion rectangular in cross section diskets 9i are disposed in the bottoms of grooves 90a and members 88 and 88 are drawn firmly against these gaskets by cap screws 92 passing through members 86 and 88 and into pintle member 98. Pintle 'member 90 is provided with inlet passages 98h, discharge passages 98o and a l central lubricating passage 98d as already riescribed in connection with pintle 22.

Pintle 98 like pintle 22 is connected to the adapter members at eachside thereof by tension members which are somewhat elastic. With the construction shown in Fig. 2 the nozzle members are rigid with the adapter members in a direction at right angles to the bolts 23. In the construction shown in Fig. 8 there will be some elasticity or flexibility in the connection between the nozzle members and the adapters. The pipes 89 and 89a due to their U-shape will have some give or elasticity and a more exible construction is thus provided. Separate cap screws are also used instead of the continuous bolts 23.

In Figs. 9, l0 and 11 another construction of the piston assembly is shown. A cylinder block 95 is shown, which block is provided with only one cylinder 95a longitudinally thereof. There will, of course, be a plurality of these cylinders circumferentially of the block. In the pumps having just the one cylinder longitudinally of the cylinder block the cross head 98 which recipro cates in a bore 95h in the block is of cylindrical form. Said cross head has the inwardly extending reduced portion 96a forming the piston core about which extends the shell or sleeve 91 of the piston, the same being counterbored at its inner end to receive the holding nut 98 threaded on a reduced portion-of core 96a and beingdisposed in the inner end of the shell 91. Cylinder 95a has a port 95o for the passage of oil from and into the pintle. Cross head 98 has extending transversely thereof and supported on roller bearings 99 therein, the pin |88. Pin |80'has secured to its endsjat each side of block the roller IIII which as already described will run against the vis supplied to intake member |4c.

inner side of the ring which moves the cross heads and pistons. as shown in Fig. 1 is considerably larger than the cylinder bore and the diameter of this bore is somewhat larger than the width of the cylinder block. A keyway 96h is formed in one side of cross head 96 in which is disposed a key member |02 secured in cylinder block 95 by the pin |03. The core member 96a is also provided with a plurality of annular grooves 96C.

In the pumps havingmore than one cylinder lengthwise of the cylinder block the cross heads 40 as shown in Figs. l and 3 are rectangular in cross section and with this construction and with more than one cylinder there can be no movement of pin 42 about a radial axis extending centrally therethrough. Ithas been found, however, that in the pumps having just one cylinder in the cylinder block where the cross head is cylindrical in cross section that the cross head pin will rotate about a radial axis of the cylinder block which would also be the central axis of the cross head. This causes the rollers ||l| to engage the sides of the cylinder block and also to engage the sides of the members carrying the rotating ring. To prevent this rotation the key |02 is provided. The cross head reciprocates and this key slides in the keyway or spline 96h so that any rotary movement oi' cross head 96 is prevented.

In operation, liquid, which is vcustomarily oil, Shaft 52 is rotated, thus rotating a cylinder block 32. Ring 56 is likewise rotated by the component forces of rollers 42a and 45a. When ring 56 is in position concentric with the pintle 22 the rollers 45 travel thereabout and there is no movement of the pistons radially of the cylinders in the cylinder block. Ring 56 can be moved to the right or left as seen in Fig. 1 by movement of the ring or rotor guide member 6|. This is accomplished either manually or automatically by means not shown. When ring 56 is moved to position eccentric with the pintle 22 there will be an inward movement of the pistons at one side of the ring and an outward movement `of the pistons at. the other4 side of the ring. The rollers 45 will remain in contact with ring 56 and at the side Where the ring is closest to the cylinder block they will be pushed inwardly and will move outwardly against the ring by centrifugal force -at the other side. As the pistons 43 move outwardly they exert suction and the oil is drawn through pipe I6, through the adapter member I1 andpthrough the inlet passages of the pintle, then out through the ports 22e into the cylinders. As the pistons move around and are pushed inwardly this oil is forced out through the outlet or exhaust ports of the pintle, into the eX- haust passages, out through member 2| and pipe 29 and through the discharge member I8. The stroke of the pistons can be regulated or adjusted by movement of the ring 56, which, as stated, is accomplished by moving member 6|. The member 6| and parts carried thereby has considerable mass or weight and thus has considerable inertia. It is important that in the operation of the pump this member and ring 56 be very easily moved. When the pump is part of a control system,^such as a system used for steering a battleship, slight movements of the ring are necessary. For this reason the rollers 63 and 12 are provided so that rotor guide 6| can be moved with a very small force and is thus very easily controlled'.

The bore for cross head 96 i As stated, there is a small space between the cylindrical portion of the pintle between bearings 33 and 34 and there is usually a iilm of oil between these parts. The cylinder block runs on the bearings 33 and 34. When the pump is operating with ring 56 out of the concentric position there is high pressure on the oil and the oil lm on the pintle can be maintained without difficulty. If the pump is not operating under pressure the lubrication of the pintle may not be maintained. In order to overcome this difficulty the bore 22c is provided and oil is forced through this bore from connection 3l by some suitable oil circulating means and this oil is forced out through the passages 22cc to insure that the pintle will be properly lubricated. To further insure a proper bearing should any friction occur between the rotating cylinder block and said portion of the pintle the shell 22f is provided. This will insure that there will be a proper bearing between the materials of the cylinder block and shell should the cylinder block for any reason rub against the pintle. The pintle may possibly be deected by the high pressures or the difference between the suction and discharge temperatures causing thermostatic action to cause such contact. The grooves 22g are provided to equalize the radial pressure on the pintle.

The grooves 40e are provided within the piston shells to prevent air being forced by suction along the inner sides of the piston shells 43a. The grooves 40e fill with oil and passage of air is thus prevented.

The shells or piston sleeves 43a also are made ofmaterial having a coeicient of expansion greater than the coeicient of expansion of the material of the cylinder block. When the pump is operating the oil becomes heated under the high pressure and the pistons thus also become heated. The pistons will expand, however, and maintain a good seal' in the cylinders due to their greater coeicient of expansion. The lower ends of the pistons as stated have rather thin walls and the high pressure of oil against or within the ends of the pistons will expand the inner end of the piston somewhat, causing it to maintain a closer fit in the cylinder. The collar or roller 42a being integral with the pin 42 prevents any end slip of this pin. 'I'he lubrication of the bearings is assured by the forced feed of oil through bore 22e of the pintle as well as by the flow of oil caused by the pressure. 'I'he oil forced through the passages 22C will pass to the'outer end of the pintle into the bearings 34. Any oil forced between the pintle and cylinder block will also pass out through the bearings 34. The oil will pass into the opening at the end of the pintle and between the same and the drive shaft. The

oil will pass through the passages 52e, into the space inside of cover plate 54 and through bearings 46. Oil will also pass from the cylinders out along the rollers 45, through the passages 51a and 58a and through the bearings 60 so that all of these parts will be positively lubricated.

vOil will also pass from around the pintle between The oil after passing through the various bearings passes to the bottom of the housing which forms a sump and is provided with a suitable drain.

By having the cylinders arranged longitudinally in pairs and closely adjacent as shown in Fig. 3, it is possible to have a common port leading from the cylinders to the pintle. This is an important part of the construction as it enables the bearings 33 and 34 to be brought closer together which insures that the cylinder block and pintle will rotate more readily in concentric relation. Due to the high pressures used there is a tendency to deflect the pintle which is of cantilever construction. It will be noted that thecylinder block runs about bearings which are concentrically arranged and that one set of bear-` ings is within a smaller radius or circumference than the other. Thus bearings 34 are smallest, being on the small end of the pintle, bearings 33 are somewhat larger while. the bearings 46 on which the cylinder block also runs are of considerably greater diameter. It is a very difficult task and one almost impossible to mechanically construct such bearings so that they will at all times be in perfect concentric relation. There can be more variance provided for in the larger bearings than in the smaller bearings. In order to insure that the bearings 33 and 34 will be maintained concentric with the pintle the` yielding construction formed by the leather' washers 2l and 54o and the cork rings 28 and 54d is provided. Should the pintle be deflected by the pressure or for any other reason bearings 33 and 34 will continue to be concentric with the pintle and the pintle can shift laterally a short distance adjacent its supported end and the variation will be made in the bearings 46 which can more easily stand a slight variation. The movement, of course, Will be exceedingly small. Were the bearings at the fixed end of the pintle rigid the bearings 33 and 34 would have to gyrate or run out of true and this would produce a wedging action on these bearings. At the high speeds and pressures used the mechanical problems presented are, as stated, quite diiilcult. The oil taken into the pump is usually at considerably lower temperature than the oil at the discharge side which is raised in temperature by the work x producing the pressure and friction. 'Ihis difference in temperature at the sides of the pintle is one factor tending 'to deect the pintle by thermostatic action. g

From the above description it is seen that l applicant has provided a pump of the rotary radial piston type whicl! will operate with great eiciency and accuracy. The various problems -V encountered in the construction of such a pump have been solved by the construction and-arrangement above described. The pump has been amply demonstrated in actual practice, found to be very successful and eiiicient and is being commercially made.

It will, of course, be understood that vvarious changes may be made in the form, details, arf

rangement and proportions of the parts, without*v departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out the obiectsabove set forth in the parts and combinations of parts dis- .l

closed and defined in the appended claims.

What is claimed is:

l. A pump of the rotary radial piston hav-v ing in combination, a pintle having a portion integral therewith having substantially parallel sides, spaced -intake and spaced discharge passages extending longitudinally of said pintle, said pintle having an opening through one of said parallel sides communicating with said intake 2. Thestructure set forth in claim 1, said last mentioned means comprising tensioned members extending through said intake and outlet members and at opposite sides of said pintle.

'3. A pump of the rotary radial piston type having a pintle flexibly supported only at one end, a cylinder block rotatable about said pintle and running about bearings spaced longitudinally or said pintle and carried thereby, a housing, said cylinder block also running on a bearing in said housing adjacent the supported end of said pintle, said last mentioned bearing being of larger diameter than said first mentioned bearings, said cylinder block being movable a short distance relatively to said pintle transversely thereof adjacent the supported end of the latter.

4.' A pump of the rotary piston type having in combination, a housing, a pintle having inlet and outlet passages leading therefrom, members rigidly secured to said housing, curved pipes connected respectively to said members, members disposed at either side of said pintle for'supporting one end thereof and having passages communicating respectively with said inlet and discharge passages, means for clamping said last mentioned members to said pintle for supportingV said pintle, saidcurved pipes being connected at the .other ends respectively to said ilrst mentioned members. A l

5. A pump of the rotary piston type having in combination, a housing, a pintle having a portion vwith inlet and outlet passages, members at either side of ,said pintle having passages communicating respectivelywith said passages, means for clamping said pintle between said members, said members having provision for slight movement in planes respectively parallel to the axis of said pintle, members rigidly secured to said housing at opposite sides of said pintle, and conduits connecting said rst mentioned members and last mentioned members constructed and arranged to permit movement in a direction at right angles to said rst mentioned movement.

6. A pump of the rotary piston type haying in combination, a housing, a pintle having inlet and discharge passages leading therefrom, members at opposite sides of said pintle having passages communicating with said passages, means for 'securing said members and `pintle together, inlet and discharge members secured to said housing, and conduits having U-shaped bends respectively securing said last mentioned members and said nrst mentioned members.

JOHN B. EAWLEY, Jn. 

